Etch mask

ABSTRACT

Provided is a etch mask that prevents the separation of the etch mask which occurs in the vicinity of an end portion of a material to be etched during etching step. The etch mask is one formed on a surface of a material to be etched and comprising collected linear masks. A portion of a linear mask positioned in the vicinity of an end portion of the material to be etched becomes a wider portion as compared with the remaining portion or a zigzag portion. As required, the middle portion of the linear mask also becomes a wider portion or a zigzag portion.

FIELD OF THE INVENTION

[0001] The present invention relates to an etch mask which is formed ona surface of a material to be etched, and more specifically to an etchmask, particularly a stripe-shaped etch mask or a diffractiongrating-shaped etch mask, useful in forming a required pattern on asemiconductor device.

BACKGROUND OF THE INVENTION

[0002] The present invention relates to the formation of an etch mask ona substrate. As one example of such an etch mask, FIG. 1 shows a priorart etch mask 2 a having a predetermined pattern and formed on a surface1 a of a precursor device 1. The prior art mask 2 a is stripe-shaped,with a plurality of linear, parallel masks 2 b each having apredetermined line width and length. The surface of the masked precursordevice 1 is then etched according to the mask pattern. The etch mask 2 ais then removed, and another semiconductor material, which may includebut is not limited to InP, GaAs, AlGaAs, GaP, InGaAs, AlInGaP, InGaP,GaInAsP, GaN, ZnSe, or CdTe, is laminated thereon as required.

[0003] A major problem in semiconductor fabrication is the failure ofthe mask during processing. Specifically, if etch mask 2 a separatesfrom the surface 1 a of the precursor device 1 by peeling, delaminatingor some other process, or tears or is cut, then the semiconductormaterial positioned below the disturbed mask portion could be exposed toetchant, and the integrity or functioning of the resultant device couldbe jeopardized.

[0004] The separation or breakage of etch mask 2 a may occur due tovarious factors. If an oxide layer is formed on surface 1 a prior tomasking the surface, then the mask material, such as a photoresist, maynot properly bond or attach to the surface. Semiconductor surfaces aretypically treated with hydrogen peroxide or other agents to remove oxidelayers and prepare the surface prior to masking. Improperphotolithography processing is another cause of separation or breakageof an etch mask. Yet another cause of separation is damage to the maskduring etching.

[0005] These problems with the prior art can be addressed by means ofappropriate previous treating of a surface of the precursor device,appropriate photolithography developing, and appropriate control of theetching. Despite these precautions, the separation of etch masks duringetching continues to be a problem.

[0006] One problem that has been particularly difficult to solve is theseparation of the etch mask during etching that results from excessiveetching. In particular, isotropic etching of substrate material near theedge of the mask can result in undesirable modifications of the surfacemorphology and can weaken the bond between mask and substrate. This isillustrated in FIG. 2, which is a cross-sectional view taken along theline II-II in FIG. 1. As shown by the horizontal arrow, etchingperpendicular to the surface of precursor device 1 can reduce thecontact area between mask 2 b and that device. This may result inseparation of the semiconductor material positioned just below etch mask2 a in the vicinity 1A, and as a result etch mask 2 a can lift away fromthe precursor device.

[0007] Separation of an etch mask may damage the semiconductor devicebeyond repair for its intended use. Thus for the structure illustratedin FIG. 1, separation of the mask may limit the usefulness ofsurrounding areas or even the entire device, and further processing mayresult in a defective product. Detection of potentially defectiveproducts is difficult, and usually does not occur until later in themanufacturing process. The delay and additional processing results in anincrease in manufacturing costs.

[0008] As described above, the separation of etch masks in manufacturingof a semiconductor device has been a serious problem.

[0009] Japanese Unexamined Patent Publication No. Hei. 9-232682discloses one method that addresses the problem of separation. Theetching process of that method is performed by the use of a etch mask inwhich all ends of the adjacent linear mask 2 b have been connected andintegrated as shown in prior art FIG. 3, or with an etch mask in which alinear mask perpendicular to all linear masks 2 b has been provided oneach linear mask 2 b shown in FIG. 3, as shown in prior art FIG. 4.

[0010] However effective these techniques are in the prevention ofseparation of the etch mask, other problems result from its use. Oneproblem that may occur from the use of an etch mask is a variation inetch rate. At the point where adjacent linear masks are connected toeach other, a smooth flow of etchant is suppressed. The resultantvariation in etch rate can result in an unacceptable variation of thedimensional accuracy of the device.

[0011] Another problem is defectiveness in layer formation when anothersemiconductor material has been laminated as a layer after etching. Forexample, in the manufacturing of a light-emitting semiconductor device,when a mesa stripe formed by etching is formed as a current contractedportion, a current blocking layer needs to be grown on the side of thiscurrent contracted portion, that is, an etched portion. However, adesired current blocking layer is difficult to grow in the peripherywhere adjacent linear masks are connected to each other, that is, an endportion of the mesa stripe.

SUMMARY OF THE INVENTION

[0012] An aspect of the present invention is to provide an etch maskthat can prevent separation of the etch mask in the vicinity of an endportion of an etch mask.

[0013] To attain the above-mentioned aspect, the present inventionprovides a etch mask formed on a surface of a material to be etchedcomprising collected linear masks, where a portion of the linear mask inthe vicinity of an end portion of the etch mask or in the vicinity of anend portion of the material to be etched has a wider portion or azigzag-shaped portion as compared with the remaining portions.

[0014] It is one aspect of the present invention to provide an etch maskon a material to be etched comprising an elongated portion, and an endmember connected to said elongated portion, where the width of saidelongated portion adjacent to said end member is an end width, wheresaid end member has a maximum extent measured in the direction of saidend width, and where said maximum extent of said end member is greaterthan said end width.

[0015] It is another aspect of the present invention to provide a maskpattern comprising a plurality of portions on a material to be etched,said plurality of portions including two end portions, and an elongatedportion disposed between said two end portions, where in the vicinity ofsaid two end portions, said elongated portion has an end width, said endportion has a maximum extent measured in the direction of said endwidth, and where said maximum extent is greater than said end width.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016]FIG. 1 is a partial top plan view showing one example 2 a of aconventional stripe-shaped etch mask;

[0017]FIG. 2 is a partial cross-sectional view taken along the lineII-II in FIG. 1;

[0018]FIG. 3 is a top plan view of an etch mask disclosed in JapaneseUnexamined Patent Publication No. Hei. 9-232682;

[0019]FIG. 4 is a top plan view of another etch mask disclosed inJapanese Unexamined Patent Publication No. Hei. 9-232682;

[0020]FIG. 5 is a partial top plan view showing one example 12 a of astripe-shaped etch mask according to the present invention;

[0021]FIG. 6 is a partially enlarged view in the vicinity of an endportion of the etch mask 12 a;

[0022]FIG. 7 is a schematic diagram showing the etch mask 12 a of thepresent invention with a material to be etched;

[0023]FIG. 8 is a partial top plan view showing another example 22 a ofa stripe-shaped etch mask according to the present invention;

[0024]FIG. 9 is a partial top plan view showing another stripe-shapedetch mask 32 a according to the present invention;

[0025]FIG. 10 is a partial top plan view showing still anotherstripe-shaped etch mask 32 a according to the present invention;

[0026]FIG. 11 is a sequence of cross-sectional views showing theprocedures of forming a mesa stripe on a surface of a material to beetched using the stripe-shaped etch mask of the present invention;

[0027]FIG. 12 is a partially cutaway perspective view showing alaminated structure of a DFB laser device;

[0028]FIG. 13 is a sequence of cross-sectional views showing theprocedures of forming a diffraction grating of a semiconductorsubstrate; and

[0029]FIG. 14 is a partial top plan view showing an example of adiffraction grating-shaped etch mask according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0030] One example of a etch mask 12 a according to the presentinvention will be described with reference to FIGS. 5 and 6, which showa partial top plan view showing an etch mask 12 a formed on a surface 1a of a material 1 to be etched.

[0031] Reference to the material to be etched in the present inventionrefers to material having a surface with an etch mask covering at leasta portion of the surface. Material to be etched includes for example, asemiconductor material, an insulating material, and a conductingmaterial. Further, the material to be etched includes a precursor devicein which various semiconductor materials have been laminated on asubstrate.

[0032] Etch mask 12 a comprises a plurality of linear masks 12 b, eachhaving predetermined line widths and lengths and separations, and formedon a surface of the material 1. The pattern of etch mask 12 a shown inthe Figures are illustrative, and are not meant to limit the claims ofthe present invention.

[0033] As shown in FIGS. 5 and 6, etch mask 12 a in the vicinity 1A ofan end portion of the material 1 has a wider portion 12 c. The area ofwider portion 12 c selected to provide protection from separation due toundercutting as described in the prior art.

[0034] In one embodiment, the width W of wider portion 12 c is widerthan a line width Ws of another portion of the linear mask 12 b, asshown in FIG. 6. FIG. 7 shows the extent of undercutting due toisotropic etching as dashed lines. Even after undercutting of mask 12 c,a material Id remains in contact with the mask. The greater contact areanear the end of mask 12 c acts to inhibit or prevent separation of themask from material 1. Accordingly, the separation of the entire widerportion 12 c from the surface of the material 1 to be etched does notoccur often. To allow such effects to occur, it is preferable that thewidth W of the wider portion 12 c be two times or more as large as theline width Ws of another portion.

[0035] The size of wider portion 12 c is limited by some practicalconsiderations. When the wider portion 12 c is too wide, the spacingbetween masks 12 b increases and the number of the linear masks 12 bwhich can be formed on the surface of material 1 becomes small. Also,the wider portion 12 c may suppress the smooth flow of etchant in thevicinity of the wider portion 12 c. If crystalline growth issubsequently preformed on material 1 then the width of the mask mayaffect deposition as well. Thus, for example, for MOCVD, a line 5 μmwidth Ws and a 100 μm width W disturbs the distribution of depositionprecursors to the extent that it is difficult to get a good crystalquality using MOCVD method.

[0036] The shape of materials 1 to be etched may include a circularshape, a rectangular shape and the like. Further, the kinds of thematerials 1 to be etched may include, but are not limited to, InP basedsemiconductors, GaAs based semiconductors, and GaP based semiconductors,insulating materials such as sapphire, quartz, diamond, and SiN, andvarious conducting materials.

[0037] When the material 1 to be etched is a laminated structure ofsemiconductor materials, it may be comprised of a single layer or aplurality of layers. The laminated materials may include, but are notlimited to, a III-V group compound semiconductor and/or a II-VI groupcompound semiconductor such as InP, GaAs, AlGaAs, GaP, InGaAs, AlInGaP,GaInP, GaInAsP, GaN, ZnSe and CdTe.

[0038] Additionally, the material of the above-mentioned etch mask 12 amay include, but is not limited to, any one of silicon nitride, siliconoxide, silicon oxynitride and photo-sensitive resist is preferable. Anyone of these materials can be easily applied to the formation of theetch mask 12 a of the present invention, and the reliability thereof ishigh.

[0039]FIG. 8 is a partial top plan view showing an example of anotheretch mask 22 a according to the present invention. Etch mask 22 acomprises a plurality of collected linear masks 22 b and is formed on asurface of the material 1 to be etched. And portions in each linear mask22 b positioned in the vicinity 1A of end portions of the material 1have wider portions 22 c.

[0040] In addition to wider portions 22 c at the ends of mask 22 b, asdescribed previously, etch mask 22 a has an additional wider portion 22d disposed between the ends of the mask. In the embodiment shown in FIG.8, wider portion 22 d equally divides the linear mask in thelongitudinal direction.

[0041] The positions and number of wider portions 22 d are appropriatelyselected so that the separation of etch mask 22 a can be prevented. Theformation of such wider portions 22 d can enhance the adhesion forcebetween the etch mask 22 a and the material 1 to be etched just belowthe etch mask 22 a by increasing the contact area there between even ina case where the line width of each linear mask 22 b is small.

[0042]FIG. 9 is a partial top plan view showing an example 32 a ofanother etch mask embodiment of the present invention. This etch mask 32a has a plurality of linear masks 32 b each having zigzag shapes in atop plan view in portions 32 c positioned in the vicinity 1A of the endportions of the material 1 to be etched. Specifically, the end 32 c ofthe etch mask 32 a is formed such that the mask end having the samewidth as the line width Ws of the linear mask 32 b is folded zigzag fromside to side a plurality of times (the zigzag is shown as being foldedthree times, as an example, in FIG. 9).

[0043] The total elongated length of the zigzag portion in the end 32 c,that is the length obtained by the addition of lengths of all zigzagportions, is longer than the linear distance (L₀) of the linear mask 32b and the end portion of the etch mask 32 a. In other words, the contactarea between the end 32 c and the material 1 to be etched becomes largerthan that in a case the associated end is linear-shaped.

[0044] Etching of etch mask 32 a advances from the end portion of theetch mask during the etching process, decreasing the contact areabetween mask and material to be etched. However, the contact area perunit length in the end 32 c is larger than that of a simple linearshape, providing additional resistance of separation. At the same time,the advance of he separation is stopped at the folded portions in thezigzag portions. As a result, the separation of etch mask 32 a issuppressed.

[0045] A preferred etch mask 32 a shape that is effective in suppressingseparation is one with a total elongated length of the zigzag portions32 c that is two or more times the line width Ws of the linear mask 32b.

[0046] As with the previous embodiments, there are some limitations onthe size of the end or enlarged portions. If the total elongated lengthof the zigzag portions is too long, the length of the linear masks 32 bthat can be formed on the entire surface of the material 1 to be etchedbecomes to short to be useful. Further, since a smooth flow of etchantin the vicinity of the folded portions is suppressed, which may presentprocessing uniformity problems. As discussed previously, the subsequentdeposition may be affected as well, though the zigzag portion 32 c tendsto have less of an effect on deposition than does the wider portion 12c.

[0047] Additional variations on the zigzag mask are possible. Thus, forexample, a middle portion of the linear mask may be modified to includea zigzag portion, as shown in FIG. 10.

[0048] In addition to the above-mentioned formation of a mesa stripe,the mask of present invention can be used in the preparation of adiffraction grating in a distributed feedback (DFB) laser device, willbe described.

[0049] A typical mesa stripe width is usually 1 μm to several tens μmlevel. However, the period of the diffraction grating formed in the DFBlaser device is usually several hundreds of nanometers level, and theline width of one linear mask may be in the range of several tensnanometers to several hundreds nanometers.

[0050] The separation phenomenon of the mesa stripe etch mask almostoccurs during etching steps after the etch mask has been formed.However, since the line width of the etch mask used in the formation ofa diffraction grating is significantly narrow, the adhesion propertiesbetween an etch mask and a semiconductor substrate is deteriorated andsuch problems often occur that the associated etch mask is separatedeven in the steps of forming the etch mask.

[0051] When an etch mask for a diffraction grating is formed, a negativeresist is applied to a semiconductor substrate (a material to be etched)and usually subjected to heat treatment, and then a desired pattern of adiffraction grating is patterning-exposed with an electron beam drawingdevice. After that, the patterning-exposed portion iscross-linking-cured and is subjected to a developing process by analkali solution so that non-patterned portions are removed bydissolution to form a diffraction grating-shaped stripe of resist.

[0052] Finally, dry etching is conducted, for example, and a diffractiongrating having a desired period and a line width is patterned on asemiconductor substrate (a material to be etched).

[0053] In this series of formation processes, the resist is etched by analkali solution during the above-mentioned developing, and thedissolution of the resist advances from an end of the resist. Separationof the resist thus proceeds from the end of the resist.

[0054] As explained above, an etch mask having a wider portion or azigzag portion near its end is effective in suppressing separation ofthe resist and greatly improves the ability to form diffraction gratingsand other devices. In particular, separation is prevented by increasingthe width of the wider portion or by lengthening the zigzag portion.However, if the width of the wider portion is too wide, the widthbecomes larger than a desired period of the diffraction grating.Accordingly, the end portions of the resists (linear masks) become closeto each other or connected to each other and proper etching in the laterdry etching steps is suppressed and further, desired crystalline growthis not conducted in the later layer laminating steps. Further, if thelength of the zigzag portion is too long, an appropriate diffractiongrating cannot be formed. For such reasons, the upper limits areproperly determined.

EXAMPLES Examples 1 to 8 and Comparative Examples 1 and 2

[0055] By the use of an etch mask according to the present invention, amesa stripe was formed as follows. First, as shown in FIG. 11(a), asurface of a material 1 to be etched having a semiconductor laminatestructure containing an active layer was sufficiently subjected to apretreatment. Typical pretreatment includes an acid bath, followed by arinse and drying with nitrogen gas. Acid baths can include on or more ofphosphoric acid, hydrochloric acid, and sulfuric acid. Then a 100 nmthick SiN_(x) film 2 was formed by a plasma CVD process.

[0056] After pretreatment, a known photoresist was applied onto theSiN_(x) film 2 to form a 1.5 μm thick resist film 3 (FIG. 11(b)). Then,by applying a known photolithography technique to the resist film 3,resist masks 3 a corresponding to the etch mask 12 a or 22 a shown FIG.5 or 8 respectively in the top plan view were patterned (FIG. 11(c)).Subsequently, as shown in FIG. 11(d), an SiN_(x) film 2 positioned at aportion other than just below the resist mask 3 a was etched by an RIE(Reactive Ion Etching) process and the entire resist mask 3 a wasremoved whereby various stripe-shaped mask bodies 12 a (22 a) shown inTable 1 were formed on the surface 1 a of the material 1 to be etched(FIG. 11(e)).

[0057] Then, the resultant structure was transferred to an etching stepand exposed material portions, which were not covered with stripe-shapedmask bodies 12 a (22 a), were etched to form mesa stripes (currentcontracted portions) on the surface of a substrate (FIG. 11(f)).

[0058] The state of separation in the stripe-shaped mask bodies 12 a (22a) was inspected immediately after the etching step. The inspectionresults are shown in Table 1 together with the size factors of thelinear masks.

[0059] As apparent from Table 1, the separation or peeling of the etchmask is significantly reduced or does not occur at all for stripe-shapedmask bodies 12 a (22 a) having wider portions. Slight separation wasfound only in a linear mask having no wider portion in its middleportion. As explained above, the usefulness of forming a wider portionin the middle portion of the mask is clear. TABLE 1 Presence or Sizefactors of linear masks absence of wider Width of wider portion in Linewidth of portion in the State(*) of the vicinity of end linear maskmiddle portion of separation just after portion (W:μm) (Ws:μm) W/Wslinear mask etching step Comp. example 1 4.5 4.5 1 Absent 10-20%separated Comp. example 2 3.0 3.0 1 Absent 10-30% separated Example 19.0 4.5 2 Absent Not separated Example 2 9.0 4.5 2 Present Not separatedExample 3 6.0 3.0 2 Absent Not separated Example 4 6.0 3.0 2 Present Notseparated Example 5 6.75 4.5 1.5 Absent 5% or less separated Example 66.75 4.5 1.5 Present 2% or less separated Example 7 4.5 3.0 1.5 Absent7% or less separated Example 8 4.5 3.0 1.5 Present 3% or less separated

Examples 9 to 18 and Comparative Examples 3 to 6

[0060] To form a DFB laser device shown in FIG. 12, an n-InP bufferlayer 42, an MQW-SCH layer 43, and an under portion 44A of a spacerlayer of p-InP were sequentially laminated on an n-InP substrate 41, anddiffraction gratings were formed on the under portion 44A of the spacerlayer as will be described later. Note that a laminated structure fromthe substrate 41 to the under portion 44A of the spacer layer isreferred to as a material 1 to be etched.

[0061] As shown in FIG. 13(a), an about 100 nm thick electron beamdrawing negative-type resist 4 was applied onto the material 1 to beetched with a spin coater, followed by heat treatment.

[0062] Then, by the use of an electron beam drawing device, adiffraction grating pattern was drawn on the negative-type resist 4 asshown in FIG. 13(b). The resultant drawn pattern is shown in FIG. 14.After that a predetermined heat treatment and developing process wereperformed, and portions of a unexposed resist were removed to expose thesurfaces 1 a of the material to be etched as shown in FIG. 13(c). Then,dry etching was conducted to pattern a diffraction grating 5 as shown inFIG. 13(d).

[0063] The size factors of the resultant diffraction grating 5 are shownin Table 2. Also the state of peeling or separation of a resist (etchmask) just after a developing process is also shown in Table 2.

[0064] As apparent from Table 2, separation is reduced moresignificantly than in Examples 3 to 6, with wider portions having littleor no separation. Specifically, when the width (Wy) of the wider portionis set to two times or more the line width (Wx) of the linear mask, noseparation occurs. TABLE 2 Size factors of linear masks Width of widerPitch between Line width of portion in the diffraction Length ofState(*) of linear mask vicinity of end gratings linear mask separationjust after (Wx:nm) portion (Wy:nm) (Wz:nm) (Wp:μm) etching step Comp.example 3 100 100 300 20 About 20% separated Comp. example 4 50 50 30020 80% or more separated Comp. example 5 100 100 500 20 About 20%separated Comp. example 6 50 50 500 20 80% or more separated Example 9100 150 300 20 None Example 10 100 200 300 20 None Example 11 50 75 30020 5% or less separated Example 12 50 100 300 20 None Example 13 50 150300 20 None Example 14 100 150 500 20 None Example 15 100 200 500 20None Example 16 50 75 500 20 5% or less separated Example 17 50 100 50020 None Example 18 50 150 500 20 None

[0065] While the above examples describe the use of a dry etchingprocess, wet etching may be used. If the etchant of wet etching does notchemically react on the negative resist, then no SiN_(x) underlayer maybe required. If the wet etchant chemically reacts with the negativeresist, then a SiN_(x) underlayer may be required. As an example ofprocessing in this case, the mask is prepared by photolithography. A dryRIE step is then used to etch the SiN_(x) layer, followed by wet etchingof the patterned substrate.

Examples 19 to 26 and Comparative Examples 7 and 8

[0066] Various stripe-shaped mask bodies were formed on a material to beetched in the same manner as in Examples 1 to 8, except that the etchmask was the etch mask 32 a shown in FIG. 9 and the etch mask shown inFIG. 10. The resultant structure was transferred to an etching step.Then, the exposed portions not covered with the stripe-shaped etch maskwere etched to form mesa stripes (current contracted portions) on thesurface of a substrate.

[0067] The state of peeling or separation in the stripe-shaped maskbodies was inspected just after the etching step. The inspection resultsare shown in Table 3 together with the size factors of the linear masks.

[0068] As apparent from Table 3, the separation of the etch mask wassignificantly reduced or did not occur at all for stripe-shaped maskbodies having zigzag portions. TABLE 3 Size factors of linear masksPresence or absence Line width of Total elongated of wider portion inState(*) of linear mask length of the zigzag the middle portion ofseparation just after (Ws:μm) portions (L:μm) L/Ws linear mask etchingstep Comp. example 7 4.5 — — Absent 10-20% separated Comp. example 8 3.0— — Absent 10-30% separated Example 19 3.0 6.0 2 Absent 2% or lessseparated Example 20 3.0 6.0 2 Present Not separated Example 21 3.0 15.05 Absent Not separated Example 22 3.0 15.0 5 Present Not separatedExample 23 4.5 9.0 2 Absent 2% or less separate Example 24 4.5 9.0 2Present Not separated Example 25 4.5 22.5 5 Absent Not separated Example26 4.5 22.5 5 Present Not separated

[0069] After the etching process, all mask bodies were transferred to acleaning step and the state of separation in the mask bodies just afterthe cleaning step was inspected. Slight separation was observed only ina linear mask having no wider portion at the middle portion. Based onthe fact, as explained above, the usefulness of forming a zigzag portionin the middle portion of the mask is clear. As described above,according to the etch mask of the present invention, by forming a widerportion or a zigzag portion in a linear mask positioned in the vicinityof an end portion of a material to be etched, or if necessary by forminga wider portion or a zigzag portion in at least one portion other thanthe portion in the vicinity of the end portion, the separation of theetch mask in an etching step and the following cleaning step can beprevented, and at the same time, the occurrence of etching variations inthe etching step and the layer defects in the layer laminating stepafter the etching step can be prevented.

[0070] By the above-described effects, the yield in manufacturing thesemiconductor device can be enhanced and the cost reduction (workingman-hour, costs in members and the inspection costs) can be realized.Further, an array-structured device comprised of a plurality of mesastripes and a diffraction grating-built in DFB laser device can be alsostably manufactured.

What is claimed is:
 1. An etch mask on a material to be etchedcomprising: an elongated portion, where the width of said elongatedportion is measured substantially perpendicular to the direction ofelongation; and an end member connected to said elongated portion, wherethe width of said elongated portion adjacent to said end member is anend width, where said end member has a maximum extent measured in thedirection of said end width, and where said maximum extent of said endmember is greater than said end width.
 2. The mask pattern of claim 1,where said end member is a first end member and further including asecond end member on a material to be etched and connected to saidelongated portion, where the width of said elongated portion adjacent tosaid second end member is a second end width, where said second endmember has a maximum extent measured in the direction of said second endwidth, and where said maximum extent of said second member is greaterthan said second end width.
 3. The mask pattern of claim 1, wherein saidelongated portion is a first elongated portion, and further including asecond elongated portion on a material to be etched and connected tosaid end member, where the width of said second elongated portion ismeasured substantially perpendicular to the direction of elongation,where the width of said second elongated portion adjacent to said endmember is a second end width, and where said maximum extent of said endmember is greater than said end width.
 4. The mask pattern of claim 1,wherein said maximum extent of said end member is at least twice thansaid end width.
 5. The mask pattern of claim 1, wherein said end memberis adjacent to the edge of the material.
 6. The mask pattern of claim 1,wherein said first end member has an end member length measuredperpendicular to said end width, and wherein said end member covers anarea on the material to be etched that is greater than the product ofsaid end width and said end member length.
 7. The mask pattern of claim1, wherein said end member describes a shape on the material to be etch,and where said shape is a circle, a square, or a zigzag.
 8. The maskpattern of claim 7, wherein said shape is a zigzag, where said zigzaghas a total elongated length, and where the total elongated length ofsaid zigzag is at least twice said end width.
 9. The mask pattern ofclaim 1, wherein said material to be etched includes a semiconductormaterial or an insulating material.
 10. The mask pattern of claim 1,wherein said etch mask is silicon nitride, silicon oxide, siliconoxynitride, or photo-sensitive resist.
 11. The mask pattern of claim 2,wherein said elongated portion is a rectangular portion extending fromsaid first end to said second end.
 12. An etch mask comprising aplurality of mask patterns as in claim 2, wherein each of saiddirections of elongation are substantially parallel.
 13. The etch maskof claim 12, wherein said etch mask is a stripe-shaped etch mask or adiffraction grating-shaped etch mask.
 14. The etch mask of claim 12,wherein at least one of said plurality of said first and second endmembers are adjacent to an edge of said material.
 15. A mask patterncomprising: a plurality of portions on a material to be etched, saidplurality of portions including two end portions, and an elongatedportion disposed between said two end portions, where the width of saidelongated portion is measured substantially perpendicular to thedirection of elongation, where in the vicinity of said two end portions,said elongated portion has an end width, said end portion has a maximumextent measured in the direction of said end width, and where saidmaximum extent is greater than said end width.
 16. The mask pattern ofclaim 15, wherein said maximum extent is at least twice than said endwidth.
 17. The mask pattern of claim 15, wherein at least one of saidtwo end members is adjacent to the edge of the material.
 18. The maskpattern of claim 15, wherein said end portion has an end member lengthmeasured perpendicular to said end width, and wherein said end membercovers an area on the material to be etched that is greater than theproduct of said end width and said end member length.
 19. The maskpattern of claim 15, wherein said end member describes a shape on thematerial to be etch, and where said shape is a circle, a square, or azigzag.
 20. The mask pattern of claim 19, wherein said shape is azigzag, where said zigzag has a total elongated length, and where thetotal elongated length of said zigzag is at least twice said end width.21. The mask pattern of claim 15, wherein said material to be etchedincludes a semiconductor material or an insulating material.
 22. Themask pattern of claim 15, wherein said etch mask is silicon nitride,silicon oxide, silicon oxynitride, or photo-sensitive resist.
 23. Themask pattern of claim 16, wherein said elongated portion is arectangular portion.
 24. An etch mask comprising a plurality of maskpatterns as in claim 15, wherein each of said directions of elongationare substantially parallel.
 25. The etch mask of claim 24, wherein saidetch mask is a stripe-shaped etch mask or a diffraction grating-shapedetch mask.
 26. The etch mask of claim 25, wherein each of the pluralityof said two end portions are adjacent to an edge of said material.